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authorHans de Goede <hdegoede@redhat.com>2023-04-04 14:02:47 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-04-05 21:23:02 +0300
commite506731c8f35699d746c615164ed620cd53c00ca (patch)
treef0e7fd545195f557d0fec148cf2d87c13c35f746 /drivers/acpi/acpi_video.c
parent78dfc9d1d1abb9e400386fa9c5724a8f7d75e3b9 (diff)
downloadlinux-e506731c8f35699d746c615164ed620cd53c00ca.tar.xz
ACPI: video: Make acpi_backlight=video work independent from GPU driver
Commit 3dbc80a3e4c5 ("ACPI: video: Make backlight class device registration a separate step (v2)") combined with commit 5aa9d943e9b6 ("ACPI: video: Don't enable fallback path for creating ACPI backlight by default") Means that the video.ko code now fully depends on the GPU driver calling acpi_video_register_backlight() for the acpi_video# backlight class devices to get registered. This means that if the GPU driver does not do this, acpi_backlight=video on the cmdline, or DMI quirks for selecting acpi_video# will not work. This is a problem on for example Apple iMac14,1 all-in-ones where the monitor's LCD panel shows up as a regular DP connection instead of eDP so the GPU driver will not call acpi_video_register_backlight() [1]. Fix this by making video.ko directly register the acpi_video# devices when these have been explicitly requested either on the cmdline or through DMI quirks (rather then auto-detection being used). [1] GPU drivers only call acpi_video_register_backlight() when an internal panel is detected, to avoid non working acpi_video# devices getting registered on desktops which unfortunately is a real issue. Fixes: 5aa9d943e9b6 ("ACPI: video: Don't enable fallback path for creating ACPI backlight by default") Cc: All applicable <stable@vger.kernel.org> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpi_video.c')
-rw-r--r--drivers/acpi/acpi_video.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 97b711e57bff..c7a6d0b69dab 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -1984,6 +1984,7 @@ static int instance;
static int acpi_video_bus_add(struct acpi_device *device)
{
struct acpi_video_bus *video;
+ bool auto_detect;
int error;
acpi_status status;
@@ -2045,10 +2046,20 @@ static int acpi_video_bus_add(struct acpi_device *device)
mutex_unlock(&video_list_lock);
/*
- * The userspace visible backlight_device gets registered separately
- * from acpi_video_register_backlight().
+ * If backlight-type auto-detection is used then a native backlight may
+ * show up later and this may change the result from video to native.
+ * Therefor normally the userspace visible /sys/class/backlight device
+ * gets registered separately by the GPU driver calling
+ * acpi_video_register_backlight() when an internal panel is detected.
+ * Register the backlight now when not using auto-detection, so that
+ * when the kernel cmdline or DMI-quirks are used the backlight will
+ * get registered even if acpi_video_register_backlight() is not called.
*/
acpi_video_run_bcl_for_osi(video);
+ if (__acpi_video_get_backlight_type(false, &auto_detect) == acpi_backlight_video &&
+ !auto_detect)
+ acpi_video_bus_register_backlight(video);
+
acpi_video_bus_add_notify_handler(video);
return 0;